Scanning device



Sept? 10, 1946 c. c. l- UNDY ET AL 2,407,310

- SGANNING DEVICE Filed Feb. 27, 1943 4 sheets-sheet ,2

INVENTORS C:C.LUNDY H' LANGSTROTH ATTORNEY Sept. l0, 1946.

c.-c.'LUNDY ET AL SCANNING DEVICE Filed Feb. 27, 1945 4 shets-sheet 5 ATTGRNEY H, LANGSTROTH Patented Sept. l0, 13946 SCANNING DEVICE Clarence C. Lundy, Floral Park, N. Y., and Hall- Langstroth, Greenwich, Conn., assignors to Sperry Gyroscope Company, Inc.,V Brooklyn, N. Y., a corporation of New York Application February 27, 1943, Serial No. 477,466

18 Claims. (Cl. Z50- 11) This invention relates to scanning apparatus for projecting and receiving beams of radiant energy such as high VYfrequency radio beams and is more particularly concerned with a special movement-controlling mechanism for the apparatus.

In accordance with the preferred embodiment of the invention showing the same as a wide angle scanning device, the reflector or scanning member of a short wave antenna is continuously ro'- tated about a rst or spin axis and at the same time is oscllated about a second or nod axis.

One of the features of the present invention resides in the provision of lmeans for selectively arresting the scanning member at any desired position in the range of its permitted oscillatory movement while maintaining continuous motion about the spin axis. v

A further provision of the invention consists in the utilization of a single drive means for obtaining motion about the spin and nod axis with the employment of a clutch or disengageable connection between the nod determining mechanism and the drivev Imeans which is simultaneously disengaged when the nod asserting means of the apparatus is rendered effective.v

Other features and structural details of the invention will be apparent from the following description when read in relation to the accompanying drawings, wherein Fig. 1 is an elevation partly in section, of a preferred embodiment of the invention wherein the reflector is oscillated through an eccentric drive, and an electrically controlled clutch is provided fcr arresting oscillation; s

Fig. 2 is a'section along line 2-2 of Fig. l, illustrating how high frequency energy is introduced into the reiector;

Fig. 3 is a section along line 3;-3 of Fig. 1, illustrating the oscillation arresting mechanism in plan; l f

Fig. 4 is an enlarged elevation, partly in section, of the oscillation drive and arresting means for controlling oscillation of the reflector;

Fig. 5 is a section along line E-E of Fig. 4 illustrating further the clutch in the mechanism of Fig. 4;

Fig. 6 is an elevation, partly in section, of a further embodiment of the invention wherein the oscillation mechanism controls a stop selector switch device; l'

Fig. 7 is a fragmental View in elevation illustrating a further manner'of converting translation drive movement to oscillation of the reflector; y

Fig. 8 is an elevation View of a further modi- -fled form of our invention;

Fig. 9 is a section view taken along line 9 9, in Fig. 8;

Fig.A 10 is a detail view of the potentiometer illustrated in Figs. 8 and 9; and

Fig. 11 isan enlarged vertical section of the scanning mechanism shown in Figs. 8 and 9.

As shown in Fig. 1, a yoke II is formed with a depending hollow cylindrical collar I2 which projects into a drive mechanism casing I3. Collar I2 is suitably supported on the casing I3 as by bearings I4 and I5, for rotation about an axis A-A.

Yoke II, as shown in Fig. 2, is provided with4 aligned bearings II'v in its arm for supporting a reflector mounting member IE for oscillation about axis `B---B which, is preferably at right angles to axis A-,-A. Axis 'B-B is at right angles to the plane of .the paper in Fig. 1, being indicated therein atuB. `Abracket I1, rigidly fastened to member I8, projects therefrom and carries aV reflector unit I8 having a parabolic reiiector surface I9. The axis C-C of reflector I8 is mutually perpendicular to axes A-A and B-B respectively.

At the end of casingv I3 opposite the reector I8, a shaft 2I, driven by a suitable motor (not shown) extends Awithin the casing and is connected by gears 22 and 23, shaft 24 and gear 25 to a gear 25 rigid with the end of collar I2. Thus when shaft 2I is driven, collar I2,and the whole reflector assembly carried thereby are continuously rotated about the spin axis A--A at predetermined speeds. This accomplishes one scanning movement of the reflector.

Reflector ymount member I6 is formed with spaced lugs 21 yextending rearwardly from the reflector and providing a bifurcated pivoted connection withY a link 28. Link 28 is also pivoted to an arm 28 rigidly connected, as by collar 3|, to one end of a ,slideable sleeve 32 extending through collar. I2.

vlleyond the point it projects from the Yother end of the collar I2 within casing I3, sleeve 32 is formed as a strap fitting about an eccentric cam 4I fixed to a shaft 42. A helical gear 43 is xed to shaft 42 Vmeshed'with another helical 3 gear 44 fastened, as by pin 45, to a countershaft 45.

Referring now to Fig. 4, a gear 41 is freely rotatably mounted on the other end of countershaft 45 and is meshed with a drive gear 48 rigid with drive shaft 2l. To countershaft 46 there is keyed a lcylindrical bushing 49 on which is freely rotatably mounted a ratchet member I having an interrupted annular flange 52 projecting back axiaily within a, suitably formed groove 53 between bushing 49 and gear 41.

Referring now to Fig. 5, flange 52 is formed to include a plurality of axial slots 54, preferably equispaced as shown. Opposite slots 54, the

inner periphery of groove 53 is provided with axially extending plane surfaced recesses 55. Each slot 54 contains a cylindrical roller 56 hav,- ing a diameter slightly larger than the width of groove 53 but less than the radial width of the space lbetween the outer periphery of groove 53 and the adjacent wall of recess 55. The circumferential dimension of each slot 54 is preferably slightly larger than the diameter of the roller 56 thereii to permit a small displacement of the roller circumferentially of the flange.

The above described connection between gear 41 and ratchet member 5I functions as a clutch in fulfilling the purposes of the invention. Gear i1 rotates o-nly in the direction shown by the arrows in Fig. 5. With gear 41 driven in the direction of the arrow in Fig. 5 and flange 52 free to move in the same direction as a result of ratchet 5l being unrestrained by pawl 62, gear d1 rolls roller 56 after it in the same direction carrying flange 52 before it until roller 56 enters the narrowed down or restricted area of groove and .becomes wedged 'between the adjacent walls of groove 53 and recess 55 so that flange 52, ratchet 5l, bushing 48 and gear 46 areV thereby positivelydriven in the same direction as gear 41. V/'hen flange 52 is seized and held stationary by pawl G2 and a brief interval thereafter ratchet 51 is likewise seized and held by pawl 6I, roller 55 is displaced from its wedging position to be- 'come freely rotatable within groove 53 and to ratchet 5l without departing from the spirit of a the invention.

Ratchet 5| is one part of the resilient coupling, the other part of which is a ratchet member 51 rigid with gear 44. and journaled on the projecting cylindrical hub 58 of ratchet 5l. coiled spring 59 has its opposite ends anchored in ratchet members 5l and 5l', and is coaxial with shaft 46 as shown in Fig. 4. Spring 59 permits flange 52 to move relative to ratchet 51 and bushing i9 suciently to allow roller 56 to move from its wedged to its free rolling position and vice versa. As wil1 appear any equivalent flexible coupling may be used between ratchet members 5l and 51 without departing from the spirit of the invention.

Thus, when ratchet member 5| is driven by gear 41,-gear 44 is driven through the resilient coupling to rotate eccentric 4l. Eccentric 4l causes oscillation oflever 36 about xed pivot 31 to thereby reciprocate sleeve 32 parallel to axis A--Z-l. The bearing ring at 33 permits simultaneous rotation of sleeve 32 about axis A-A. As sleeve 32 reciprocates, it operates through arm 29 .and link 28 to rock the reflector mount about axis B-B, the angular spreadl of this rocking movement on opposite sides of axis C-C being determined by the relation of the cam and link mechanism. Preferably, the reflector is rocked through an angle of about 26 to each side of axis C-C, Fig. 1, a total sweep of 40. This nod movement of the reflector about axis B-B takes place at a substantially lower speed than the speed of revolution of the reflector about axis A-A, and the scanning is accomplished in a substantially spiral path through a generally solid cone of 40 apex angle.

With reference to Fig. 3, the mechanism will now be described for arresting the nod ef reflector i8 in any of the plurality of manually selected positions during its 40 angular sweep, and maintaining it fixed at the nod angle during continued rotation about axis A--A.

Ratchet members 51 and 5l are adapted to be engaged in close succession by individual pivoted stop pawls El and 62 which are simultaneously actuated by the same plunger 53 of solenoid 64. A known type of spring (not shown) maintains plunger 63 extended to hold pawls 6| and 62 in the retracted dotted line position of Fig. 3 when solenoid 64 is not energized. When solenoid 64 is energized, plunger 53 is retracted, permitting suitable springs (one shown) to urge the pawls into arresting engagement with the ratchet members.

The ratchet and pawl arrangement serves as a holding means for positioning the scanning member or reector in any one of a plurality of positions within the range of the oscillatory movement thereof. This holding means is normally ineffective and, when rendered effective, operates to disengage the clutch means described so that under this condition no further movement isV communicated to the nod mechanism by the common drive shaft which continues to rotate the scanning member about its spin axis.

The selective means for controlling the operation of the solenoid 64 may be considered to include a circuit that contains the solenoid, a source of energy and a pair of switches, one of which is manually adjusted. In the present instance, the projecting reduced end 65 of shaft 45 carries a rigid radial bracket 61 mounting a conductor brush 58. The brush 5t is adapted to successively traverse a series of equispaced conductor segments 6,9 of' a commutator 19 fixed to casing I3. Conductor brush 68 is connected to a slip ring 1l mounted on the bracket G1. A conducting arm 12 mounted at 13 on post 14 yieldably engages the slip ring 1i Lead 15 connects they arm 12 and one terminal of the solenoid 64. They selective circuit further includes, lead 15 connected to the other terminal of the solenoid 64, a battery Sil, off-on switch 8i and a manually adjustable selector switch generally designated at 62. Switch 8,2 includes a settable knob 18 having an arm 16 that connects with one of a number of contact points 11, there being one co-ntact point for each of the segments 6,9- of the commutator. These individual connections are made through multiple conductor cable 83. In the present instance, thirteen contacts 11 are provided, the same having individual indications thereon showing the operator the necessary position of arm 16 to effectively control the arresting mechanism to stop the scanning member at a corresponding position in the path of its permitted oscillatory movement. Correspondingly, thirteen segments 6e are provided with angular spacings of 3. Obviously, the number of segments 69 and the angular spacing between stop positions of the scanner may be varied.

as desired without departing from the. spirit of The scanning reflector mayy be positioned at any one of thirteen positions about its nod axis over a range of 36. In operation, ther operator, for example, sets the knoby 18 to the contact on which it is positioned in Fig. 4, namely, -6. When brush 68 moves to position the segment 69 to which this corresponding contact 'I'I is connected, the circuit is closed, solenoid 64 being `energized to release the paWls GI-BZ at the proper moment to engage the ratchets 5 I-5I and correctly position thescanning member with a nod of 6 about its nod axis.

In the modification of the invention shown in Fig. 6 the reflector unit I8 nods about an axis provided by npivot connection 84 through means of link 85, arm 86 and the reciprocating sleeve 20. The sleeve may be moved by the eccentric cam mechanism previously described through means of the bail 36, one arm of which is connected to the sleeve by link 35 and the other arm of which a-s noted at 89 performs the function of ther commutator arrangement described in connection with Fig. 4. The conducting arm 89 of the bail slides over thirteen contacts 90 mounted on the frame or casing of the apparatus, contacts 90 corresponding to the segments 69 of the commutator. The same operates in connection with the selector switch 82 and detail circuit previously described to perform the function of stopping thev scanning member at a desired position within the range of its movement about the nod axis provided by pivot connection 84. The scanning member is' continuously rotated about its axis A--A by the drive means previously described, including drive gear 22' which in this construction meshes with gear 9| on the rotating sleeve 92 on which the mounting frame 93 is fixedly mounted. Rotating frame 93 has a laterally extending bifurcated portion which contains the spaced bearings which form a part of the pivotal connection 84 of the scanner mounting. Link 85 is directly connected to the'Y rear of the member I8' and moves in response to the nod driving mechanism to oscillate the memf ber about the nod axis while the member continues to spin about the axis A-A.

In the modification of the invention shown in Fig. 7, the motion of link 85 is communicated to the scanner member by means of a sector and gear connection, the respective parts of which are designated at 94 and 95.V

In the form of the invention illustrated in Figs. 8 to l1, inclusive, the scanning member 96 is mounted for movement about a nod axis B by means of a yoke 91, the spread extending arms ning member. accomplishes this purpose by the continuous movement of turntable 98 and the yoke 91 fixed thereto on which the member is mounted. l

. Means for moving the scanning member about its nod axis B is provided in this instance by a mechanism which includes link I I0, bell crank I I I engageable co-nnection for rendering the nod Y means ineffective and the arresting means effecof which pivotally support the member. Yoke 91 is xedly mounted on the bottom of a turntable 98 whose axis is defined byL bearings 99 that provide the spin axis A-A of the scanning member 96. Bearings 99 are mo-untedin the hub |00 of a fixed frame |00 o-n the top of which is mounted a casing IOI lthat contains the parts of the improved mechanism situated above the frame. Turntable 98 is fixed to 'a sleeve |02 which also includes a gear |03. Continuous rotary movement for the turntable is communicated to the sleeve |02 by way of gear |03 which isv driven by a gear |04 that is keyed to a drive shaft |05. The shaft |05 may be driven .by suitable motive means such as a motor (not shown) whose continuous motion is communicated to the same by way of the Worm |06` and worm wheel |01. Shaft I05`is suitably mounted in the frame and casing by means of bearings |08 and |09. It will be understood that the Vdescribed mechanism for spinning the scanmounted between the extending arms of the yoke on shaft II2 and the link |I3'. One end of the link |I3 is universallyv connected to one ofthe arms of the bell crank II I, the other endv of the same being pivotally connected to nod gear I|4 mounted on a stub shaft extending from the bottom of turntable 98. The. connection of the link I|3 and gear II4'is eccentric to the axis of'the gear II4` so that, as the gear rotates, oscillating movement isimparted to the bell crankv by the link which moves thescanning member about the nod axis. Gear I|4 is driven by gear |I5, coaxial with spin axis A-A, and mounted on a sleeve IIE on the upper portion of which are the concentric drive gears II'I and |I8. Gear IIB, which has the same diameter as the drive gear |03 of the mechanism by which the member is rotated, forms a part of the arresting mechanism for. controlling the movement ofthe member about its nod axis. Gear II1 is of smaller diameter than the gears I I8 and |03 and is normally effective to drive the gear II5 at a higher R. P. M. than the R. P. M. of the turntable 90. Such relative movement drives the nod gear I I4 and moves the scanning member .about the nod axis in the manner previously described.

Instead of the clutch provided in the form of the invention shown in Fig. 1, we employ a dis-r tive. In the construction shown, gear |20 which meshes rwith gear |I8 is loosely mounted on the drive shaft |05 and is supported by means of a collar. Gear I2| which meshes with gear ||`I is similarly mounted on the shaft |05. The adjacent faces of the axially spaced gears |20 and I2| have radial grooves therein which receive a tongue |22 that extends through two axial slots in the shaft |05 and is xed to an elongated pin |123 located in a central axial opening in the shaft. Pin |23'rotates with the shaft |05 Vand is axially movable therein, the parts being normally positoned as shown in Fig. 11 by means of spring |24 so that the tongue |22 engages the groove in the gear I2| lockingthe gear to the shaft |05 and y consequently driving gear II'I` to eect nodding movement of the scanning member. It rwill be understood that with gear I2I rendered effective by the disengageable connection, gear |20 and Vthe arresting mechanism controlled thereby are ineffective.

To bring the arresting mechanism into operation, pin |23 is urged in a direction to compress the spring |24. vThis movement is accomplished when a'solenoid |25 is energized by closure of switch |26. Plunger |21 at one end of the pin is raised upwardly, thus elevating the pin and moving the tongue |22 out of engagement with gear |2| and into engagement with gear |20. By this action gear I I8 is driven directly by the shaft |05. Gears I|8 and |03 which are the same diameter are then driven by the shaft |05 so that the turntable 98 and gear I I5 rotate at equal speeds. No motion in this event is communicated from gear II5 to nod gear |I4 and movement of the scanning member about its nod axis stops. When switch |26 is opened, the parts return to their normal position of operation.

1 In orderrthatthezoperator. of the apparatusabea informed ci the. ang-ularpositionof theiscanning" member at .agiven instant, a bridge circuitais em.-

ployed in Which resistors 12S-i3!) and l3'l--I32.

are situated in the=respectvefbranches thereof. Resistors l` and |32 aressitu'atediina poten? tiometer. I331mounted on.the :yoke .91 of Ytheape paratus. The moving arm 134! of .thespotenti'ometer is controlled from shaitl I2 of theubell crank.:l Hl by way of gearsl I'andil35.. An ammeter I31I is connected across. the branches. of the bridge? circuit,..the pointer of which'. swingsithrough an.

arc'following themovementof Lthe scanningmemiber about .its nod'axis.'A Thescale of the'ame meter is calibrated in degrees to indicate-:the instantaneous. position; of thelmember.' By close ing the switch at .a .desiredtima .the operator is thus able to arrest thescanningfmembergat any particular nodv angle desired..

Since many changes Acould be'made intheLabove: construction and many .'apparentlywidely differ-'- ent-l embodiments of thisinvention could bemade without departing from thescopexthereof, it is;in tended that all matter contained inA the above description or shown inithea'ccompanying .drawe ings shall be interpreted asillustrativefan'd. not

inv a limiting sense.

Having described our invention, what We. claim.

and desire to secureby LettersPatentis:

1. A scanning apparatus; comprising. a...scanf ning member, drivingmeansgmeans actuatedbyl said driving means for spinning saidscanning member abo-ut a rs.taxis, means vactuated by said driving means for oscillating 'sa-id scanning member through a predetermined angle about a second axis, arresting means -for stopping said oscillating means without interruption ofthe rotation of said scanning member about said first axis, and

selective means for presetting said arrestingl means to stop the oscillation of said scanning member at a chosen angle ofnod.

2.A An apparatus as claimed in claim l, in which said scanning memberis the reflector of an antenna that receives or transmits high frequency electrical energy.

3. In a scanning apparatus, a rotatable scanning member, drive 'meansfor rotating said member about a rst axis, means mounting said,mem. ber for oscillation about a second axis disposed at an angle to said rst axis, normally effective means actuated by said drivemeans .for oscillating said member about said second axis, and stop means, rendering said oscilla-tion actuatingmeans ineffective, for selectively arresting said'member at a desired position in thepath of its movement about the second axis.

4; In a scanning apparatus, a scanningmemeber mounted for movement about a spin.axis,

means for spinning said member, amounting lfor.y said member providing a second axis about which.

the member nods, means for noddingsaidlmember, normally inactivestopmeansfor said. node ding means for arresting said member` inoneof.

a plurality of positions in the range Oitsmovement about the second axis, and selectiveA means for rendering said stopmeans active, saidgmeans,

for spinning said member and said means. for nodding said member being drivenv from a common drive shaft.

5. A scanning apparatuscomprising; a scanning member mounted for" movement about a spinV axis and a nod axis, drive means bothforspirr-Y ning and nodding said member,`and astop means for selectively arrestingl the nod'u movement of the member at one ofaplurality'ofpositions*While'- the member.: continues.; to: move z about'. its L. spin;

6. ,An apparatus `as r.claimed in claim 5, in which-f said scanning memberis thejleector of a radiator.

onreceiverfor h iglrfrequency electrical energy..

7. .In a scanning apparatus, a movable scanning member, drivezmeans both for spinning said mem-- ber aboutia rst axis and for. nodding said member about a1secondcaxisldisposedfat an angle .tothe rst axis, and stop-means;y for the nod driving means for. selectively, arresting 1 the'` member at one of a.: plurality Aof'` positionslin .thezrangeof its movement about the second axis;t

8. InaY scanning apparatus, .aamovable scanning, member, drive meansifor. spinningisaid member. about,- a vertical. axisdrivecmeansdfor node ding saidzmember. about a.:horizontal axis,.stop,` means forl said. nod driving. means :for arresting the member.v at oneof a pluralityof positions ,in the. range, of nod. movement thereof,.e1ectro. magnetic. means. for. controlling said stopzmeans',.

and selective switch means forfactuating saidelectromagnetic controlling means..

9. 1n .a scanning apparatus, a scanning .member mounted for-move1nent;about two perpendicularly disposedaxes, mechanism for spinning saidwmem.- ber'about onezof the axesgxmechanisnrforrnodding the me-mber about'the. other 'axis including normallyinactive means for holding themember in one of a plurality of nod positions,4 a unidirectional drive meanscommon to said mechanisms,

clutch means connecting-said..I drive', meansY and said nod mechanism, andy selective.means for rendering` said holding meansactive to disengage said clutch meansv as saidzscanning member-arrives at arpredetermined 'angle of: nod.

10. An apparatus as claimedin claimz9', in whichr Said selective meansisxprovided by `a; circuit having a solenoidand va 'controlling switchA therein.

11. YIn ascanning apparatus, a, scanning. member mounted for oscillationy abouti anA axis, .normally operative, mechanism for constantly oscillating .said member including normally; inactive means for ho-lding` thermember inA onexof a.. plurality of, positions, drive means forA saidconstantly oscillating mechanism, clutch. means .connecting said drive means `and said .oscillating mechanism, and means for ysimultaneously disengaging said clutchmeans and selectively'crendering.said lio-ldsY ing means-active;

12. An apparatus as claimedin c1aim.l1,.in whichsaid holding means includes a'pair of 'coaxial, springcoupled ratchets and afpair: of co operating; normally inactive; pawls.

13.'Anantenna forshort wave. electrical energy including, a reflector havingrvertical and horizontal supporting, axes, means for. spinning the'reector aboutfitssvertical axis, means for nodding,` thefreflector: about its horizontal axis, drive means'forsaidspinning and nodding means,

clutch means connecting 4said drive and lnodding ding. said' member` about. a second axisv disposedV atan angle tov the first axis,.normally; inactive.

means for arresting the member at a preselected said member providing a second axis about which` the member nods, means actuated from said spinning means for nodding said member, normally inactive means for arresting said member to position the same as desired Within the range of its movement about the nod axis, and means for simultaneously rendering the nodding means inactive and said arresting means active.

17. In a scanning apparatus, a scanning member having freedom of rotation about two angularly displaced axes, driving means for spinning said member about a first axis, normally active means cooperative with said spinning means for nodding said member about a second axis, m'eans for disengaging said nodding means from said spinning means, and means for accurately stopping said scanning member at a desired position about the second axis thereof.

18. In ascanning apparatus including a scanning member, driving means for spinning said scanning member about a first axis, and oscillating means actuated by said driving means for nodding said scanning member about a second axis, the combination comprising means for arresting the nod of said scanning member about said second axis Without stopping its spin about said first axis and selective means for presetting said arresting means to stop the oscillation of said scanning member at a chosen angle of nod.

CLARENCE C. LUNDY. HALL LAN GSTROTH. 

